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Rich

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Re: 2019 sea ice area and extent data
« Reply #1650 on: July 15, 2019, 01:44:55 PM »
Per the chart in post 1625, it looks like we've got about 900k km2 or  ~ 15k km2 / day to catch the 2012 CAB area minimum.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1651 on: July 15, 2019, 02:11:05 PM »
NSIDC Total Area as at 14 July 2019 (5 day trailing average) 5,426,278 km2
                        
Total Area         
 5,313,418    km2      
-612,186    km2   <   2010's average.
-753,096    k   <   2018
-1,332,318    k   <   2000's average.
         
Total Area Change   -113    k   loss
Peripheral Seas   -8    k   loss
Central Seas__   -93    k   loss
Other Seas___   -12    k   loss
         
Peripheral Seas         
Bering _______    0    k   gain
Baffin  Bay____   -6    k   loss
Greenland____    1    k   gain
Barents ______   -3    k   loss
         
CAB Seas         
Beaufort_____   -6    k   loss
CAA_________   -11    k   loss
East Siberian__   -26    k   loss
Central Arctic_   -17    k   loss
         
Kara_________   -8    k   loss
Laptev_______   -14    k   loss
Chukchi______   -10    k   loss
         
Other Seas         
Okhotsk______    0    k   gain
St Lawrence___    0    k   gain
Hudson Bay___   -13    k   loss

- Area loss 113 k, 16 k more than the 2010's average loss of 97 k on this day.
- Total area Lowest, 254 k LESS than 2016, and 50 k LESS than 2012.

Area loss staying above average, difference with 2012 narrowing, with 2016 widening.

Other Stuff
Weather
GFS  showing temperature anomalies in the range +0.9 to 0 degrees celsius over the next 10 days.
Intially
- over the Arctic Ocean itself temperatures a bit above average,
- the CAA & Baffin Bay mostly warm,
- Western Canada stays mostly cool.
- Alaska and Western Siberian  warm,
- Central Siberia  cool.
But as the days go by all Siberia and Alaska cools down.

Over the next 5, or even 10, days it looks like a fairly significant low sits over the central Arctic Ocean north of Central / Eastern Siberia and elsewhere a high sits in the North Atlantic and another high over Greenland. The strongish anticlockwise winds matching but opposite to the normal clockwise movement of the Beaufort Gyre are maintained, starting as northerly winds from the CAA and the North Greenland coast. Strong winds and rain also from the South up Baffin Bay into the CAA at least for the first few days.

What all this means for melt is.... ?
Is this weather pattern there for the long-term?

A cliff or not a cliff** See below
We are in the period of maximum daily area loss that lasts until late July.
Overall, Area losses in July to date above average. Being a five-day trailing average, higher than average area loss will continue for 2-3 days at least.

It looks like Fram export has stalled, with most area losses in the arc from the ESS along the Russian shore and down to the Barents. The CAA is showing signs of melt strongly increasing.

It is definitely a steep downward slope

However, the ESS is not a slope, or a cliff. It is a yawning abyss, but is the yawn decreasing?

NSIDC 5 day Area could/would/should/will/will-not continue in pole position for about one week/two weeks/the rest of July/the entire remaining melt season (delete as applicable).
________________________________________________________________________
ps: Meanwhile, Extent loss continues to be well below average. Dispersion graph in next post (after lunch.)
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1652 on: July 15, 2019, 02:39:27 PM »
Area is reducing at a faster rate than extent. The ice is becoming more disperse - so here is a dispersion graph. Pretty well much at a record high with 2012.
_____________________________________________
This will usually reverse when refreeze starts, i.e. concentration will increase.
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1653 on: July 15, 2019, 03:28:57 PM »
The CAA and melt ponds.

The snow-melt gif attached (click to start) shows that in July the islands of the CAA have been losing snow at a rate of knots, consistent with the GFS showing the CAA as warm in July so far.

The sea ice gif attached (click to start) shows Baffin Bay, Hudson Bay and the Southern channels of the CAA losing ice, while the northern part suddenly seems solid again.

Oren's plain language summary of how melt ponds forming and draining and fooling the sensors seem to still be in play. In other words, the area loss in the graph attached probably understates the amount of melt, i.e. melt even more above average than shown.


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Rich

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Re: 2019 sea ice area and extent data
« Reply #1654 on: July 15, 2019, 03:33:01 PM »
CAB area loss of 17k is pretty close to the ~ 15k / day pace needed to keep pace with 2012 CAB area minimum. 

Losses outside the CAB are robust. 96k is another day of the average approaching 4% of the total non-CAB ice remaining.

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Re: 2019 sea ice area and extent data
« Reply #1655 on: July 15, 2019, 04:21:58 PM »
NSIDC daily extent

Glen Koehler

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Re: 2019 sea ice area and extent data
« Reply #1656 on: July 15, 2019, 05:17:58 PM »
Watching the ice flow back toward the AO from the Nares also illustrates this,

AO = Arctic Oscillation atmospheric pattern, not a place.  I don't understand what AO means here.

Tealight's High Arctic analyses also use the same 7 seas. That is really useful- being able to match extent, area and volume, to AWP.

What is AWP?  It is not in the glossary.

Neven

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Re: 2019 sea ice area and extent data
« Reply #1657 on: July 15, 2019, 05:27:25 PM »
Albedo Warming Potential. I'll add it to the glossary.
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Re: 2019 sea ice area and extent data
« Reply #1658 on: July 15, 2019, 05:30:17 PM »
Albedo Warming Potential

The theoretical amount of heat that the arctic ocean can absorb, based on the latitude, time of year and ratio of ice to open water.

it does not factor in cloud cover.

AFAIK

Rich

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Re: 2019 sea ice area and extent data
« Reply #1659 on: July 15, 2019, 05:30:40 PM »
AO is Arctic Ocean

RoxTheGeologist

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oren

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Re: 2019 sea ice area and extent data
« Reply #1661 on: July 15, 2019, 05:48:56 PM »
AO meant Arctic Ocean in that specific post. But I had to scratch my head a long time, and initially thought maybe it was the Atlantic Ocean. So, the acronym used wasn't the best exemplar of good communications...

Patrice

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Re: 2019 sea ice area and extent data
« Reply #1662 on: July 15, 2019, 09:27:15 PM »
Area numbers are going down, and extent are sort of "stalling". I have nothing but my memory, but I have imagination that when wind drastically changes direction, the extent numbers stall and area numbers not so much, and typically, extent loss becomes more pronounced in a couple of days. But then again, it might be just an illusion.

Killian

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Re: 2019 sea ice area and extent data
« Reply #1663 on: July 16, 2019, 05:09:18 AM »
Watching the ice flow back toward the AO from the Nares also illustrates this,

AO = Arctic Oscillation atmospheric pattern, not a place.  I don't understand what AO means here.

Tealight's High Arctic analyses also use the same 7 seas. That is really useful- being able to match extent, area and volume, to AWP.

What is AWP?  It is not in the glossary.

Aware, but context is unmistakable as, clearly, the Arctic Oscillation is not a location and cannot be "flowed back to."

I'm a veeeeeeeery slow typist and make many errors so even the shortest post takes too much time, thus I abbreviated because I couldn't remember which specific sea is above Nares and couldn't use CAB and didn't feel like typing Arctic Ocean... Ironic given needing to write this post.

I teach language and expect context to be used by people of normal intelligence. I doubt the stress was overmuch...?

Still, will try to memorize all the little sea names for this rather pedantic group. ;-)

Cheers

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1664 on: July 16, 2019, 05:52:51 AM »
JAXA ARCTIC EXTENT :- 7,496,597 km2(July 15, 2019)

- Extent is 2nd lowest in the satellite record, 150 k above 2011.
- Extent loss on this day 75k, 2k less[/b] than the average loss on this day of 77 k.
- Extent loss from maximum 6,775 k, 339 k (5.3%) greater than the average of 6,435 k loss from maximum by this day,
- On average 65.1% of the melting season done, with 60 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 4.05 million km2, 3rd lowest in the satellite record , and 0.87 million km2 above the 2012 low of 3.18 million km2.

Other Stuff
Weather
GFS  showing temperature anomalies in the range +0.9 to 0 degrees celsius over the next 10 days. Over the next 5, or even 10, days it looks like a fairly significant low sits over the central Arctic Ocean north of Central / Eastern Siberia and elsewhere a high sits in the North Atlantic and another high over Greenland. The strongish anticlockwise winds matching but opposite to the normal clockwise movement of the Beaufort Gyre are maintained, starting as northerly winds from the CAA and the North Greenland coast. Wind and rain also from the South up Baffin Bay into the CAA at least for the first few days.

What all this means for melt is.... ?
Is this weather pattern there for the long-term?

Ice Melt Outlook
We are now in the period of maximum daily extent loss that lasts until the end of July and then very gradually declines. Immediate weather outlook suggests a cooler Arctic.

Extent loss in the last few days well below average,, but area loss well above.

The June volume data persuaded me to drop my minimum guesstimate to below 4 million km2 from exactly 4 million km2. A mistake?
______________________________________________________________
« Last Edit: July 16, 2019, 11:00:04 AM by gerontocrat »
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Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #1665 on: July 16, 2019, 06:07:26 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

July 15th, 2019:
     7,496,597 km2, a drop of -74,577 km2.
     2019 is 2nd lowest on record.
     (2012 highlighted).
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

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Re: 2019 sea ice area and extent data
« Reply #1666 on: July 16, 2019, 06:50:58 AM »
Semimonthly BOE evaluation

July 15 extent was 7,496,597 km^2. With on average 60 days to go until the end of the melt season on September 13th, we now require a daily drop of -108,277 km^2 for a BOE to occur. (See Attachment 1).

Total extent loss thus far in July 2019 was -1,539,884 km^2. And total extent loss so far this season is -6,774,524 km^2. This has resulted in the current average daily drop of -54,196 km^2. If the month of July ended today, this would be the 7th fastest rate of melt for the same period for the years 2007-2019. (See Attachment 2). 
Additionally, if the melt season ended today, -54,196 km^2 would place 2019 as 5th out of 13 for the years 2007-2019.

Looking only at the month of July so far, we have averaged -102,659 km^2 per day. If the month of July ended today, this average daily drop places July 2019 as 1st out of 13 (2007-2019) in average daily July melt. (See Attachment 3).

I said in a previous post that we would need to have the strongest July melt ever in order for a BOE to occur. And while a BOE will likely not occur this year, we have still managed to have the strongest July melt so far.



Also, I have previously been posting the individual months for the first attachment rather than the excel sheet of the entire melt season. It allowed for us to be "on pace" at the first of the month if there was a big enough drop on the first, even if we were not on pace the day before. Confusion ensues.
« Last Edit: July 16, 2019, 06:59:20 AM by Ktb »
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Killian

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Re: 2019 sea ice area and extent data
« Reply #1667 on: July 16, 2019, 07:33:03 AM »
As for the 15th:

Quote
7/15 - 7.35M km sq.

With '11 dropping 90k into the 15th, 2019 may well keep pace to give me a rather precise short-term prediction...

...or not. 2019 couldn't manage a measly 80k drop to stay within the prediction window, instead dropping a rounded 70k km sq to stand at 7.5M km sq.

The sea ice hates me, clearly.

I started doing this bc I often see comments on the site about the notorious inaccuracy of long-term projections from the various data sources. I have had some success at meta-analysis of ASIE, not in terms of km sq, but in terms of relative direction up and down and a rough idea of how much. In conversations with Paul Beckwith on Facebook, I correctly predicted 2013 and '14 would be higher than 2012 while he was citing Wadhams and calling for  BOE. I made no prediction in 2015 bc of family issues. However, in Aug. 2015, at RealClimate, I predicted a new or near-new ASIE for 2016 or 2017 due to an analysis of the effects of El Nino's on ASI that supposedly doesn't exist, but I think does. (You have to look at 24 months post-EN, not just one summer.)

As you all know, 2016 came in 2nd. And, 2016 spent something like **seven months** hitting record lows, just not in the summer. Good enough for a prediction a year in advance given the great difficulty predicting ASI.

I didn't think either 2017 or 2018 would come close to 2012, or challenge 2016. No specific numbers, just meta stuff.

Basically, I'm curious about short-term predictions, so started this. So far, sucking pretty bad on the daily level despite some earlier success. One thing I miss that I no longer find on the ASIGraphs page is the ice speed and drift graphic. Anyone know where to find that? It's very useful for analyzing extent - at least for me.

Ah, well, onward!

Quote
7/16/11 - 7.24M km sq.

That's a drop of roughly 110k km sq from the previous day. Gerontocrat notes the cooling phase currently dominating, so let's keep this simple: Nope. 2019 will not drop 110k for the 16th and will likely end up another 20 ~ 50k km sq higher than 2011, or close to 200k higher extent than 2011. Call it 7.43.

EDIT/UPDATE: '19 dropped 10k more than I predicted, 80k, to 7.42 vs. -110k for '11, but I'll take it as error bars. Definitely didn't keep pace with 2011, as predicted. Currently +180k to 2011.

Quote
7/17/11 - 7.15M km sq

2011 drops a further 90k and I see no reason for 2019 to keep pace. Looking at what all you good people have to say, winds, temps here and there, there's little to point to strong compaction. Say, 7.35.

EDIT/UPDATE 7/16: 2019 starts from 7.42, not 7.43, so revise to 7.34. (I'd like to increase this drop, but will live or die with the original predictions. Looking at a 190k spread, if so. News around the fora indicates it may decrease, though, or stay the same.)

Edit/Update 7/17: Dropped a full 100k to 7.32. Should've increased it. 2011 leads by 170k.

Quote
7/18/11 - 7.06M km sq.

Same here... 7.26....

Edit/Update 7/17: I called 80k. Don't think it will be that low. While winds overall seem to be suggesting expansion, there's some strong stuff forecast over Siberia that could spread the ice.

Sticking w/ previous 80k call: 7.24, +180k relative to '11.

Revising for current conditions: 7.22, or 100k drop, +160k to '11.

Quote
7/19/11 - 7.00M km sq.

...and here...  7.2. Winds really look dominant in all the right areas to either expand where there's room or toward compaction where there's no room to compact.

(I think ASI Area would be much more interesting to track, and far more relevant.)
« Last Edit: July 18, 2019, 06:01:23 AM by Killian »

uniquorn

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Re: 2019 sea ice area and extent data
« Reply #1668 on: July 16, 2019, 10:38:54 AM »
Quote
One thing I miss that I no longer find on the ASIGraphs page is the ice speed and drift graphic
http://osisaf.met.no/p/osisaf_hlprod_qlook.php?year=2019&month=05&day=22&action=Today&prod=LR-Drift&area=NH&size=100%25

Neven

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Re: 2019 sea ice area and extent data
« Reply #1669 on: July 16, 2019, 10:55:08 AM »
I think he refers to the CICE/HYCOM/ACNFS map that was put out by the Naval Research Laboratory. I had to remove it unfortunately, because it kept causing security warnings in my browser (and probably those of other people too). I replaced it with the OSI-SAF drift map, but that isn't a forecast.
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Killian

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Re: 2019 sea ice area and extent data
« Reply #1670 on: July 16, 2019, 11:51:42 AM »
Uniquorn, Neven, thanks.

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Re: 2019 sea ice area and extent data
« Reply #1671 on: July 16, 2019, 01:30:54 PM »
BTW the OSI-SAF drift map shows a lot of outward drift in the past two days, both in ESS and towards Laptev/Kara. Good for short-term extent, bad for long-term health.

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Re: 2019 sea ice area and extent data
« Reply #1672 on: July 16, 2019, 01:42:56 PM »
Looks to me like the forecasted weather is about as good as it can possibly get for ice retention. In North east Siberia it looks more like Late August than Mid July with some air frosts and even patchy snow cover at times. Really does seem like the ultimate test of melting momentum vs meterology.

Also annecdotally it does seem like cold and cloudy July's seem to becoming more of the norm, is there a mechanism for this related to a negitive feedback?

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Re: 2019 sea ice area and extent data
« Reply #1673 on: July 16, 2019, 01:58:42 PM »


Also annecdotally it does seem like cold and cloudy July's seem to becoming more of the norm, is there a mechanism for this related to a negitive feedback?

More open water leads to more evaporation and more clouds which keep the Arctic covered - probably one of the reasons for the "stall" after 2007 (the other is probably bathymetry I guess). On the downside, the same happens during winter, when clouds stop outgoing radiation, keeping the Arctic warmer

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1674 on: July 16, 2019, 03:16:38 PM »
NSIDC Total Area as at 15 July 2019 (5 day trailing average) 5,221,614 km2
                        
Total Area         
 5,221,614    km2      
-603,733    km2   <   2010's average.
-712,418    km2   <   2018
-1,335,604    km2   <   2000's average.
         
Total Area Change   -92    k   loss
Peripheral Seas   -12    k   loss
Central Seas__   -69    k   loss
Other Seas___   -11    k   loss
         
Peripheral Seas         
Bering _______    0    k   gain
Baffin  Bay____   -5    k   loss
Greenland____   -3    k   loss
Barents ______   -4    k   loss
         
CAB Seas         
Beaufort_____   -9    k   loss
CAA_________   -9    k   loss
East Siberian__   -16    k   loss
Central Arctic_   -7    k   loss
         
Kara_________   -10    k   loss
Laptev_______   -6    k   loss
Chukchi______   -11    k   loss
         
Other Seas         
Okhotsk______    0    k   gain
St Lawrence___    0    k   gain
Hudson Bay___   -11    k   loss

- Area loss 92 k, 11 k LESS than the 2010's average loss of 103 k on this day.
- Total area Lowest, 273 k LESS than 2016, and 27 k LESS than 2012.

Area loss dipping below average, difference with 2012 narrowing, with 2016 widening.

Other Stuff
Weather
GFS  showing temperature anomalies in the range +0.9 to 0 degrees celsius over the next 10 days. Over the next 5, or even 10, days it looks like a fairly significant low sits over the central Arctic Ocean north of Central / Eastern Siberia and elsewhere a high sits in the North Atlantic and another high over Greenland. The strongish anticlockwise winds matching but opposite to the normal clockwise movement of the Beaufort Gyre are maintained, starting as northerly winds from the CAA and the North Greenland coast. Wind and rain also from the South up Baffin Bay into the CAA at least for the first few days.

What all this means for melt is.... ?
Is this weather pattern there for the long-term?

A cliff or not a cliff** See below
We are in the period of maximum daily area loss that lasts until late July.
Overall, Area losses in July to date above average.

It looks like Fram export has stalled, with most area losses in the arc from the ESS along the Russian shore and down to the Barents. The CAA is showing signs of melt strongly increasing.

It is definitely a steep downward slope

However, the ESS is not a slope, or a cliff. It is a yawning abyss, but is the yawn decreasing? YES

NSIDC 5 day Area could/would/should/will/will-not continue in pole position for about one week/two weeks/the rest of July/the entire remaining melt season (delete as applicable).
________________________________________________________________________
ps: Meanwhile, Extent loss was well below average. But daily extent loss just went up on this day. Switcheroo?
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Re: 2019 sea ice area and extent data
« Reply #1675 on: July 16, 2019, 03:42:41 PM »
NSIDC daily extent

Rich

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Re: 2019 sea ice area and extent data
« Reply #1676 on: July 16, 2019, 05:24:24 PM »
The duality of the 2 Arctic's continues.

Area outside the CAB declined by 84.5k km2 or 3.3% while area inside the CAB declined by 7.4k km2 or only 0.3%.

It's only one day and there is plenty of time to pick up the pace, but these kind of numbers don't add up to a record (if records are the kind of thing that matter to you). We need to average ~ 15k km2 / day in the CAB to approach a record area minimum.

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Re: 2019 sea ice area and extent data
« Reply #1677 on: July 16, 2019, 07:09:43 PM »
Most CAB area losses occur during August. At this stage the stats can't predict the loss magnitude - it will be interesting.

Rich

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Re: 2019 sea ice area and extent data
« Reply #1678 on: July 17, 2019, 02:59:49 AM »
Most CAB area losses occur during August. At this stage the stats can't predict the loss magnitude - it will be interesting.

Thanks for the comment Oren.

If you look at the CAB area and extent charts that Gerontocrat shared on post #1625, it appears that there is a difference in the pattern of loss in the 2D categories.

It is extent (not area) which appears to have the disproportionate loss in August. The slope of the line indicating area loss does not appear to change much from June to August.

Please take a look and let me know if you see it otherwise.

To be clear, I'm not attempting to predict anything in this thread. I'm merely trying to point out what needs to happen in the CAB in order to establish a new minimum. It either will or will not happen.

oren

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Re: 2019 sea ice area and extent data
« Reply #1679 on: July 17, 2019, 03:37:44 AM »
Most CAB area losses occur during August. At this stage the stats can't predict the loss magnitude - it will be interesting.
If you look at the CAB area and extent charts that Gerontocrat shared on post #1625, it appears that there is a difference in the pattern of loss in the 2D categories.

It is extent (not area) which appears to have the disproportionate loss in August. The slope of the line indicating area loss does not appear to change much from June to August.
You are correct about the area average. But there is a bifurcation point that separates the low years (2012, 2016) and the high years, which the average blends together. This can be easily seen in the higher resolution Wipneus AMSR2 area chart I provided above which has all years since 2012, but is also apparent in Gerontocrat's post #1625. That point in the season has not yet been reached, but my money is on joining 2012 and 2016 in the bad August club.

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Re: 2019 sea ice area and extent data
« Reply #1680 on: July 17, 2019, 05:58:28 AM »
ADS JAXA is half an hour late on the update. I will wait a little more.
I'm very curious on today's value.
https://ads.nipr.ac.jp/vishop/#/extent

P.S:
Well, too late for me.
Have a good day, afternoon or night!
See you tomorrow [Mexico time].
« Last Edit: July 17, 2019, 06:45:42 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

wdmn

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Re: 2019 sea ice area and extent data
« Reply #1681 on: July 17, 2019, 06:58:35 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

July 16th, 2019:
     7,424,100 km2, a drop of -72,497 km2.
     2019 is 2nd lowest on record.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1682 on: July 17, 2019, 07:33:33 AM »
JAXA ARCTIC EXTENT :- 7,424,100 km2(July 16, 2019)

- Extent is 2nd lowest in the satellite record, 182 k above 2011.
- Extent loss on this day 72k, 16k less[/b] than the average loss on this day of 88 k.
- Extent loss from maximum 6,847 k, 324 k (5.0%) greater than the average of 6,523 k loss from maximum by this day,
- On average 66.0% of the melting season done, with 59 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 4.07 million km2, 3rd lowest in the satellite record , and 0.89 million km2 above the 2012 low of 3.18 million km2.

Other Stuff
Weather
GFS  showing temperature anomalies in the range +0.9 to 0 degrees celsius over the next 10 days. Negative temperature anomalies seem to be mainly in eastern Siberia.

Over the next 5 days it looks like a fairly significant low sits over the central Arctic Ocean north of Central / Eastern Siberia and elsewhere a high sits in the North Atlantic and another high over Greenland. The strongish anticlockwise winds matching but opposite to the normal clockwise movement of the Beaufort Gyre are maintained, starting as strong northerly winds from the CAA and the North Greenland coast. Wind and rain also from the South up Baffin Bay into the CAA at least for the first few days. GFS suggests that in the last few days the winds weaken.

What all this means for melt is.... ?
Is this weather pattern there for the long-term?

Ice Melt Outlook
We are now in the period of maximum daily extent loss that lasts until the end of July and then very gradually declines. Immediate weather outlook suggests a cooler Arctic.

Extent loss in the last few days well below average,, but area loss well above.

The June volume data persuaded me to drop my minimum guesstimate to below 4 million km2 from exactly 4 million km2. A mistake?
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Re: 2019 sea ice area and extent data
« Reply #1683 on: July 17, 2019, 03:04:36 PM »
NSIDC daily extent

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1684 on: July 17, 2019, 03:18:50 PM »
NSIDC Total Area as at 16 July 2019 (5 day trailing average) 5,137,444 km2

Area loss slowing
                        
Total Area         
 5,137,444    km2      
-585,084    km2   <   2010's average.
-674,368    km2   <   2018
-1,327,186    km2   <   2000's average.
         
Total Area Change   -84    k   loss
Peripheral Seas   -15    k   loss
Central Seas__   -56    k   loss
Other Seas___   -14    k   loss
         
Peripheral Seas         
Bering _______   -0    k   loss
Baffin  Bay____   -4    k   loss
Greenland____   -8    k   loss
Barents ______   -3    k   loss
         
CAB Seas         
Beaufort_____   -5    k   loss
CAA_________   -5    k   loss
East Siberian__   -11    k   loss
Central Arctic_   -19    k   loss
         
Kara_________   -6    k   loss
Laptev_______   -2    k   loss
Chukchi______   -7    k   loss
         
Other Seas         
Okhotsk______    0    k   gain
St Lawrence___    0    k   gain
Hudson Bay___   -14    k   loss

- Area loss 84 k, 16 k LESS than the 2010's average loss of 100 k on this day.
- Total area Lowest, 287 k LESS than 2016, and 11 k LESS than 2012.

Area loss dipping below average, difference with 2012 narrowing, with 2016 widening.

Other Stuff
Weather
GFS  showing temperature anomalies in the range +0.9 to 0 degrees celsius over the next 10 days. Negative temperature anomalies seem to be mainly in eastern Siberia.

Over the next 5 days it looks like a fairly significant low sits over the central Arctic Ocean north of Central / Eastern Siberia and elsewhere a high sits in the North Atlantic and another high over Greenland. The strongish anticlockwise winds matching but opposite to the normal clockwise movement of the Beaufort Gyre are maintained, starting as strong northerly winds from the CAA and the North Greenland coast. Wind and rain also from the South up Baffin Bay into the CAA at least for the first few days. GFS suggests that in the last few days the winds weaken.

What all this means for melt is.... ?
Is this weather pattern there for the long-term?
A cliff or not a cliff** See below
We are in the period of maximum daily area loss that lasts until late July.
Overall, Area losses in July to date above average, but trending downwards.

It looks like Fram export has stalled, with most area losses in the arc from the ESS along the Russian shore and down to the Barents. The CAA melt is ahead of average.

It is definitely a steep downward slope starting to ease.

The ESS was not a slope, or a cliff. It was a yawning abyss, but is the yawn decreasing? YES

NSIDC 5 day Area could/would/should/will/will-not continue in pole position for about one week/two weeks/the rest of July/the entire remaining melt season (delete as applicable).
________________________________________________________________________
Extent loss also low on this day. A cool Arctic & not enough inclement weather to stir things up?
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

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Re: 2019 sea ice area and extent data
« Reply #1685 on: July 17, 2019, 03:59:27 PM »
5 day average area loss in the CAB jumps WAY up. From 7k to 19k.

Do the math. 19k * 5 = 95k CAB loss in the last 5 days and apparently a huge chunk of that in the last 24 hours.

Why? Where? How? It's all a mystery.

Someone(s) at NSIDC have access to much more granular area data than we do and understand where losses are happening in that gigantic bucket we call "CAB".

Does anyone have NSIDC connections? I wonder if a FOIA request would result in their providing more granular CAB data?



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Re: 2019 sea ice area and extent data
« Reply #1686 on: July 17, 2019, 04:02:56 PM »
- In the six days from the 5th to the 10th of July, NSIDC extent dropped 983 million of km2 (!)
- In the six days from the 11th to the 16th of July, it has dropped 414 million of km2
However, due to the divergence caused by the storms and the further degradation of the ice, area has kept falling approximately steadily.

Do we know if this stormy weather is causing significant drop of temperature over the ice, or what is the same, some pond refreezing etc?
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Sterks

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Re: 2019 sea ice area and extent data
« Reply #1687 on: July 17, 2019, 04:32:27 PM »
5 day average area loss in the CAB jumps WAY up. From 7k to 19k.
Do the math. 19k * 5 = 95k CAB loss in the last 5 days and apparently a huge chunk of that in the last 24 hours.
Why? Where? How? It's all a mystery.
I think we discussed this before.
Because the trajectories that  cyclone winds cause on the ocean or the ice that lies on the ocean separate to each other, dispersing the ice and inflating the pack - > more extent, less area. Coriolis effect, not intuitive because the cyclone winds themselves are convergent but the ice deviates heavily to the right resulting in gradual dispersal

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Re: 2019 sea ice area and extent data
« Reply #1688 on: July 17, 2019, 04:50:21 PM »
  There is no mystery ..  the CAB is increasingly holey .. Worldview allows those who wish to use their own eyes to see what is happening for themselves . also the cracks N. of Greenland are in the CAB . The CAB measurable melt season is really only beginning . b.c.

 
« Last Edit: July 17, 2019, 07:18:58 PM by be cause »
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

oren

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Re: 2019 sea ice area and extent data
« Reply #1689 on: July 17, 2019, 05:08:08 PM »
Why? Where? How? It's all a mystery.

Someone(s) at NSIDC have access to much more granular area data than we do and understand where losses are happening in that gigantic bucket we call "CAB".

Does anyone have NSIDC connections? I wonder if a FOIA request would result in their providing more granular CAB data?
No mystery. Check OSI SAF ice drift map and you will see ice was exported out of the CAB in the direction of Laptev. But in addition, somewhere on the NSIDC website there is the comparison tool that lets you see each day's ice concentration map, and you can compare to yesterday or to 5 days before. Someone surely has the link.

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Re: 2019 sea ice area and extent data
« Reply #1690 on: July 17, 2019, 05:20:30 PM »
But in addition, somewhere on the NSIDC website there is the comparison tool that lets you see each day's ice concentration map, and you can compare to yesterday or to 5 days before. Someone surely has the link.

http://nsidc.org/arcticseaicenews/sea-ice-comparison-tool/

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Re: 2019 sea ice area and extent data
« Reply #1691 on: July 17, 2019, 05:25:59 PM »
But in addition, somewhere on the NSIDC website there is the comparison tool that lets you see each day's ice concentration map, and you can compare to yesterday or to 5 days before. Someone surely has the link.

http://nsidc.org/arcticseaicenews/sea-ice-comparison-tool/
Thanks Pragma. I just recalled that the tool is based on extent, not area. But ice concentration images can be found on UH, Uni Bremen, and NSIDC websites somewhere, should Rich decide to make the research to find what changed.

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Re: 2019 sea ice area and extent data
« Reply #1692 on: July 17, 2019, 05:35:47 PM »
Thanks Pragma. I just recalled that the tool is based on extent, not area. But ice concentration images can be found on UH, Uni Bremen, and NSIDC websites somewhere, should Rich decide to make the research to find what changed.

No worries, I just assumed that is the one you meant. I'd like to see concentration comparison but I'm not sure how you'd do it. Perhaps a subtraction with < and > in intensity? i.e. pale to dark in red and blue?

For now, I just bring up 2 instances of Charctic, and do a visual compare.

https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

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Re: 2019 sea ice area and extent data
« Reply #1693 on: July 17, 2019, 06:14:42 PM »
Thanks Pragma for the link to the excellent tool and to Oren for your general participation in this discussion

Since this is the data thread, I think it's important to differentiate between data and anecdotal sources of information.

NSIDC is providing data about sea ice area. The OSISAF ice mobility charts and concentration maps of various other agencies can not be reconciled to the NSIDC data. It's apples and oranges.

These anecdotal sources do provide insight which is useful in educated guessing about what's going on, but not clarity.

Oren, I see your input as being valuable in terms of being helpful to an observer making more educated guesses but my point here is that the NSIDC has the potential to offer more clarity. 

The CAB has 53%+ of the ice today and will increase to 80% or more as the season progresses. It's a weird data distribution when the smaller non-CAB gets divided into 14 sub-buckets and the big piece gets one.

The NSIDC can and should do better. This is not a criticism of anyone at ASIF.

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Re: 2019 sea ice area and extent data
« Reply #1694 on: July 17, 2019, 06:51:45 PM »
Rich - the fact is that each of the more southerly seas has its own unique yearly profile during both melt season and freezing season - interrelated but unique. The CAB by itself also has a yearly unique profile. The graph of the CAB posted by Oren above (Reply #1677) for CAB area shows that profile very clearly - except for minor variations area in the CAB stays a constant from January - June each year, then somewhere around July 10th give or take a week a steady decrease from that 4.2-4.4 value occurs every year. The depth of that decrease varies significantly but the duration is identical, and the refreeze begins also within quite a limited calendar period until it again rises into the 4.2-4.4 range.

This is a very different profile from the other arctic seas that have significant timing differences year to year. For this reason the standard definitions of the various seas and the lumping of the whole CAB into a single 'sea' makes sense. There being no obvious physical demarcations to further separate the CAB also makes any division to the sea artificial and prone to none meaningful variations on a yearly basis.

NB: Moderators - this discussion may have gotten off track from the data driven aspect of this thread - please feel free to delete this post or move it to a different thread.

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Re: 2019 sea ice area and extent data
« Reply #1695 on: July 17, 2019, 07:35:44 PM »
......the CAB stays a constant from January - June each year, then somewhere around July 10th give or take a week a steady decrease from that 4.2-4.4 value occurs every year. The depth of that decrease varies significantly but the duration is identical, and the refreeze begins also within quite a limited calendar period until it again rises into the 4.2-4.4 range.

The 5 day average NSIDC average that Gerontocrat reports here every day peaked at 3.2M km2 in March.

Any # of 4.2 - 4.4M km2 is coming from a different area measure. The complexity of an internet discussion involving multiple measures of the same 2D attribute (area) from a single agency (NSIDC) makes productive exchange unlikely. It becomes
too confusing.

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Re: 2019 sea ice area and extent data
« Reply #1696 on: July 17, 2019, 07:43:13 PM »
Most CAB area losses occur during August. At this stage the stats can't predict the loss magnitude - it will be interesting.



might this be where UCMiami is coming from  Rich ? As posted up the page .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

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Re: 2019 sea ice area and extent data
« Reply #1697 on: July 17, 2019, 08:04:24 PM »
Rich I am responding in the melting season chatter thread.

Rich

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Re: 2019 sea ice area and extent data
« Reply #1698 on: July 17, 2019, 08:06:44 PM »
Most CAB area losses occur during August. At this stage the stats can't predict the loss magnitude - it will be interesting.

might this be where UCMiami is coming from  Rich ? As posted up the page .. b.c.

Once again, I would refer both you and UC Miami to the excellent chart that Gerontocrat provided in post 1625. It refutes the assertion that most area loss is in August.

In certain outlier years such as 2012 and 2016 this has been the case. But it isn't a general rule.

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Re: 2019 sea ice area and extent data
« Reply #1699 on: July 17, 2019, 08:27:43 PM »
5 day average area loss in the CAB jumps WAY up. From 7k to 19k.

Do the math. 19k * 5 = 95k CAB loss in the last 5 days and apparently a huge chunk of that in the last 24 hours.

Why? Where? How? It's all a mystery.

Someone(s) at NSIDC have access to much more granular area data than we do and understand where losses are happening in that gigantic bucket we call "CAB".

I don't see anything unusual for the CAB.  Those losses are normal for this time of year:



If you want to see where exactly the losses are coming from, take a look at the NSIDC sea ice concentration images:

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/images/2019/